Infrared heating assembly



Nova 1965 i. J. BARQER 3,217,139

INFRARED HEATING ASSEMBLY Filed April 19, 1961 7 Sheets-Sheet l INVENTOR.

Ira d1 Barber Nova 9,, 1965 a. J. BARBER INFRARED HEATING ASSEMBLY '7 Sheets-Sheet 2 Filed April 19, 1961 W WW I I J INVENTOR. Bcwber Ira. all

Nov. 9, 1965 1. J. BAREiER 3,217,139

INFRARED HEATII ASESEMBLY Filed April 19, 1961 7 Sheets-Sheet 3 IN VEN TOR.

i I 6'3 I E a J\ Barber" A TTO/P/VE) Nov. 9, 1965 1 J. BARBER 3,217,139

INFRARED HEATING ASSEMBLY Filed A rillsa, 1961 7 Sheets-Sheet 4 INVENTOR.

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Nov. 9, 1965 1. J. BARBER INFRARED HEATING ASSEMBLY 7 Sheets-Sheet 5 Filed April 19 1961 A rramme Nov. 9, 1965 1. J. BARBER 3,217,139

INFRARED HEATING ASSEMBLY Filed April 19, 1961 '7 Sheets-Sheet 6 INVENTOR. [1 9. J Bomber Nov. 9, 1965 l. J. BARBER INFRARED HEATING ASSEMBLY 7 Sheets-Sheet 7 Filed April 19 1961 United States Patent 3,217,139 INFRARED HEATING ASSEMBLY Ira J. Barber, Fostoria, Ohio, assignor to Radcor, Inc., Bradner, Ohio Filed Apr. 19, 1961, Ser. No. 104,124 2 Claims. (Cl. 219347) This invention relates to electric heating apparatus, more particularly to apparatus utilizing infrared heat, and the principal object of this invention is to provide new and improved apparatus of this kind.

In the drawings accompanying this specification and forming a part of this application, there are shown, for purposes of illustration, several embodiments which this invention may assume, and in these drawings:

FIGURE 1 is a fragmentary perspective view of an oven construction illustrating an embodiment of this invention,

FIGURE 2 is an enlarged fragmentary sectional view through a bank of heaters shown in FIGURE 1, and corresponding generally to the line 2-2 of FIGURE 1,

FIGURE 3 is a fragmentary, separated perspective view of parts shown in FIGURE 2,

FIGURE 4 is an enlarged fragmentary perspective view of terminal structure employed in the foregoing construction,

FIGURE 5 is a sectional view taken through an electrical connection of the terminal structure, and corresponding generally to the line 55 of FIGURE 4,

FIGURE 6 is a sectional view corresponding generally to the line 6-6 of FIGURE 5,

FIGURE 7 is a small scale top plan view of the terminal block per se,

FIGURES 8 through 12 are bottom plan views of the terminal block illustrating a variety of electrical connections made possible by this invention,

FIGURE 13 is a separated perspective View of another embodiment of this invention,

FIGURE 14 illustrates prior art oven construction,

FIGURE 15 illustrates oven construction made possible by this invention, and

FIGURE 16 is a vertical sectional view taken through the top one of the heating sections shown in FIGURE 15.

Referring particularly to FIGURES 1 through 12, the embodiment of the invention therein disclosed comprises a plurality of basic sections 20, all substantially identical, and one or more f-rameways 21, all substantially identical. In FIGURE 1, the basic sections 20 are disposed horizontally between spaced vertically disposed frameways 21, the parts being disposed in facing relation to provide opposite walls W, W, of an oven into which work pieces (not shown) to be heated are disposed, either on a stationary support or on a conveyor which is adapted to move the work piece through the oven.

Each basic section comprises an elongated box-like housing 22 (see especially FIG. 3) which is formed as a sheet metal fabrication open at the front F. The housing has a back wall 23, and top and bottom edges of which (see top edge 24) are turned inwardly. Opposite side ends of the back wall 23 are turned inwardly to provide end walls 25, 25 each of which has its top and bottom edges turned inwardly as shown at 26, 27. Each end wall has an inwardly facing notch 28 located centrally between the top and bottom margin of the wall, for a purpose to appear.

Extending across the upper and lower front ends of the end walls are angle brackets 29, 29, each having a horizontal flange 30 adapted to lie in the same plane as the top or bottom edges 24 of the back wall 23 to provide flat surfaces for stacking basic sections one on top the other. A top angle iron 31 has its horizontal flange 32 underlying and spot welded to the top edge 24. The angle iron 31 has a vertical flange 33 which extends downwardly and is spaced from the rear wall 23. A similar bottom angle iron 34 is welded in like manner to the inner surface of the bottom edge of the rear wall and has a vertical flange 35 extending upwardly and spaced from the rear wall the same amount as the flange 33. The vertical flanges 33 and 35 are formed with screwthreaded holes therealong to receive machine screws which hold an imperforate sheet metal plate 36 against the vertical flanges 33 and 35 and spanning the end walls 25, 25 of the housing 22, to form a chamber. The end walls 25, 25 may be provided with openings 37, 37 to provide entranceway for wiring into or through the chamher, or a suitable coo-ling gas, such as air, may be circulated through the chamber.

Each end of the plate 36, adjacent to the respective housing wall 25, has a sheet meta-l shield 38 secured thereto, each shield having a foot 39 attached to the plate 36 and a wall 40 which lies inwardly of and against the respective end wall 25. Each shield wall 40 is provided with an inwardly directed opening 41 for a purpose to be explained.

A reflector 42 is disposed forwardly of the closure plate 36, the reflector in this case being formed of sheet metal and of symmetrical cross-section. As best seen in FIG- URE 3, the reflector 42 is generally trough-shaped and has flanges 43, 43 which are adapted to overly the vertical flanges of the angle irons 29, 29. The reflector flanges 43 are formed with openings to pass machine screws 44 (see FIG. 2), which screws thread into openings 45 in the vertical flanges of the angle irons 29 to hold the reflector rigidly in position across the opening into the housing 22 with the trough-like reflecting surface 46 of the reflector now forming the opening at the forward end of the basic section.

As seen in FIGURE 2, opposite ends of the reflector 45 stop just short of engagement with the adjoining shield 38 or end wall 25 to leave a slight space 47 at each end of the reflector for a purpose to be disclosed. A terminal block 50 is secured in position at the outer surface of each housing end wall 25 in a manner to be described. Four holes 52 are formed in each end wall (FIG. 3) for a purpose later to appear.

In the present embodiment, a single infrared heater 55 is illustrated, although more than one heater may be used. The single heater (or plurality of heaters) may be either a metal-sheath electric resistance heater, a quartz tube, or a quartz tungsten lamp. In any event, the heater is rod-like in appearance and has an electrical connection terminal 56 at each end. The terminal ends 57, 57 of the heater 55 pass through the openings 41 in the shields 38 and through the notch 28 in the end wall 25. The opening 41 closely receives the terminal end 57 to act as part of a baflie which restricts passage of heat to the terminal blocks 50. In the event more heaters are used, they will extend parallel to the single heater disclosed and the shield will have openings 41 corresponding to the number of heaters.

The terminal blocks 59 are preferably identical to facilitate and reduce production costs and each block comprises a base 60 (see especially FIG. 4) from which flanges 54, 54 extend. The block is rectangular in plan, as seen in FIGURE 7, and has an upstanding thickened portion 61 from which extend side walls 62, 63 between which extend three ribs 64. End ribs 65 extend from the wall 63 a like distance and the ribs define between them terminal pockets 66, 67, 68 and 69, the ribs isolating one pocket from another.

A pair of rectangular-shaped recesses 78, 70 enter the terminal block from its under surface, each being adapted to house a bus bar which is in the form of a metal strip, the bars being designated 71, 72. Pairs of similar holes 73, 74 extend between each of the pockets 66, 67, 68 and 69 and the recesses 71, 72, and a recess 75 is disposed equidistantly of and between each pair of holes.

A connector body 76 is disposable in a selected one of each pair of holes 73, 74 and in the particular embodiment disclosed the body is in the form of a round metal plug having a threaded recess 77 entering from its lower end and having a reduced upper end 78 forming a shoulder. A connector clip 79 is carried by the connector body and has a flat base portion 80 which has a hole to pass the end 78, the latter being headed over the base 80 to firmly clamp the base against the shoulder of the connector portion. If desired, a fused joint may be made between the end 79 and connector clip to improve electrical conduction therebetween.

The connector clip 79 has a threaded opening to receive a machine screw 81 and the base 80 has an angular end 82 to guide and confine a wire loop or the like which is firmly secured to the connector clip 79 by the screw 81. The wire loop is formed at one end of a connector wire 83, the other end of which is mechanically and electrically connected to the terminal 56 of the heater 55. A machine screw 84 passes through a corresponding hole in a respective bus bar and is threaded into a proper connector body to establish electrical connection from the bus 'bar to the heater terminal, as clearly seen in FIG- URE 5. It is to be noted that the length of the connector body 76 from the top shoulder to its lower end is slightly greater than the thickness of the adjacent portion of the terminal block so as to insure that the respective bus bar may be firmly connected to the connector body and the assembly may float longitudinally of the respective hole 73 or 74. The wall 63 of the terminal block is provided with several inwardly extending recesses 85 (three shown herein) to generally cradle the terminal end of the heater and thus locate the same. Since only one heater 55 is disclosed herein, only one of the recesses 85 is shown as being used.

The terminal structure just described provide-s great flexibility in electrical connection of the heater, or heaters if more than one are used. The bus bars 71, '72 may be respectively connected to line wires of opposite polarity, and the bus bars in the terminal block at the other end of the basic section may be likewise connected to line wires of opposite polarity.

Referring to FIGURE 8, a single heater is employed and its terminal 56x may be connected to bus bar 71, and thus to one side of the power line, by disposing the connector body 76 in an appropriately located hole 73 and threading the screw 84x home to effect the electrical connection. In the event it is desired to connect the terminal 56x to the other side of the line, instead of the side shown, the screw 84 is removed, the connector body 76 withdrawn from the hole 73, the connector clip 79 rotated 180 degrees, and the same connector body 76 then disposed through the paired hole 74 and the screw 84x disposed through the opening in the bus bar 72 and threaded home into the connector body.

FIGURE 9 discloses use of two heaters, the terminals 56x and 56y being respectively connected to bus bars 71 and 72. by screws 84x and 84y. It will be appreciated that the connector body 76 for the terminal 56x will be located in an appropriate hole 73 whereas the connector body 76 for the terminal 56y will be located in an appropriate hole 74. To change the connections, the connector bodies need merely be changed to the other of the pair of holes, and this is suggested in FIG. 10. Connections for three heaters having terminals 56x, 56y and 56z are illustrated in FIGURE 11, the fastening screws being designated 84x, 04y and 04z, and a change in such connections is illustrated in FIG. 12.

Referring particularly to FIGURES 1, 2 and 3, the frameways 21 are preferably similar for production economy, but may be of varying lengths according to requirements. Each is preferably formed of sheet metal and comprises an elongated channel-shaped body (see especially FIGURE 3), the bight wall 91 preferably being at right angles to the side walls 92, 92. The extremities of the walls 92 are turned inwardly to form flanges 93 which are provided with threaded holes 94 to receive machine screws 95 (FIGURE 2) to hold an imperforate metal plate 96 to close the rear side of the channel body 90.

Each body 90 may be of a length to support a plurality of basic heater section-s, and in the particular construction shown in FIGURE 3, each side wall 92 has sets of four holes 97 which match with the four holes 52 in the end wall 25 of a basic section. Screws 98 (FIG. 2) pass through aligned holes and nuts threaded on the screws hold one end of a basic section to a frameway body 90. A frameway body may be interposed between and connected to adjoining end walls of a pair of basic sections, as shown in FIGURE 2.

In line with each set of four holes 97, the front or bight wall 91 and side walls 92 are recessed as shown at 100, the front wall to provide access to the adjoining terminal block (or blocks) and to permit assembly of the blocks within the frameway body 90, and the sidewalls to provide clearance for the heater terminal ends.

Extending within the frameway body 90, preferably for the entire length thereof, is a channel-shaped sheet metal support 101 having its legs 102 spot welded to the side walls 92 and its front wall 103 interrupted to form openings 104 in line with the sets of four holes 97. The front wall 103 is formed with two pair of holes 105, each pair being vertically aligned and spaced apart a distance corresponding to the spacing of the fastening holes of a terminal block 50.

As shown in FIG. 6, the flanges 54 of the terminal block are disposed through the opening 104 in the front wall 103 of support 101 and brought to firmly bear against the rear surface of the wall 103 by passing machine screws 107 through aligned holes 105 and 106 and threading a nut 108 on the screw. The terminal block hole 106 may have a hexagonal recess 109 to receive the nut 108 and hold it against turning.

FIG. 2 illustrates the fact that the frameway 90 is wide enough to accommodate two terminal blocks 50 in side-by-side manner so that basic sections may be connect ed in line and to opposite sides of the frameway. The space 110 at the rear of the support 101 (FIG. 2) may be utilized as wire-ways for power cables and air or other suitable gas may be circulated through the frameway to cool the cables and terminal blocks. As best seen in FIG- URE 3, the side walls 92, 92 of the frameway may have knock-out plugs 111 (held in place by weakened areas) which may be removed to provide openings aligned with the openings 97 in the end walls 25 of the basic section 20. The aligned openings may provide for air circulation in the space behind the closure plate 36 or may provide for passage of line wires from one frameway to the next, or both. End caps 112 (FIGURE 1), may be utilized to close the upper and lower ends of the frameways in the event that no air circulation is necessary through the latter, or such caps may be decorative and have openings for air circulation.

Covers 115 are provided to close the recess or openings 100 in the frameway (see FIGURE 3) each cover being U-shaped in cross-section with its front wall 116 long enough to close a respective opening 100 in the front wall 91 of the frameway. The front wall 116 has a pair of holes 117 adapted to line up with a corresponding pair of threaded holes 118 in the front wall 91 of the frameway, and machine screws 119 (FIG. 2) pass through the holes 117 and thread into the holes 118 to hold the cover 115 in place.

The side walls 120 of the cover 115 are spaced to closely lie alongside the outer surface of the side walls 92, 92 of the frameway 21 and Where the latter is connected to a basic section 211, the side walls extend through the space 47 formed at the ends of the reflector 42 and overlie the shields 38. Each side wall 120 is formed with an inwardly directed recess 121 to closely pass the heater terminal and to cooperate with the shield to restrict passage of heat into the frameways. Of course, where two or three heaters are used, the walls 120 will have a corresponding number of recesses 121, as will the shields 38.

The foregoing construction provides great flexibility since oven walls, or other heater walls, may be built up to any required size, both vertically and horizontally. Thus, a standard package of a predetermined number of basic sections and frameways may be assembled in various manners to satisfy a number of heating requirements. The surfaces of the reflector 42, shields 38 and covers 115 may be suitably plated to reflect heat rays outwardly of the respective basic section.

FIGURE 13 shows a basic section which is adapted for single use and independently of frameways. The section shown in FIGURE 13 may, for example, be suspended in the manner of a fluorescent lamp. The construction disclosed in FIGURE 13 is pretty much like that previously described and similar parts will be accorded similar reference numerals with the suffix 11 added.

In FIGURE 13, end sections 125 are attached to the opposite end walls 25a, the end sections being U-shaped and having flanges 126 which are secured to end walls 25a by the screws 98a. Each section 125 is deep enough to accommodate only one terminal block 50a. The lower end of each section (FIG. 13) is closed by an imperforate sheet metal plate 127 removably secured in place by screws or the like. The upper end of each section has spaced feet 128 adapted to receive screws (not shown) which pass through holes 129 in a cover 130. The cover 130 has an angular wall 131 adapted to fit in a space such as the space 47 formed by the reflector ends. The wall 131 is formed with a pair of inwardly directed recesses 132 which closely fit around a pair of electric heaters, or around the legs of hairpin heaters 133, 133, disclosed in FIGURE 13.

The ends of the hairpin heaters are supported by the respective terminal blocks 50a in a manner previously described. To relieve the blocks 50a of undue stress caused by the cantilever support of the hairpin elements, the facing bights 135, 135 of the heating elements are connected together and to the reflector 42a by a bracket 136 which has a generally link-shaped upright section 137 formed with an opening 138 to pass one or the other of the bights and a recess 139 to receive such bights. The bracket has a foot 140 which may be suitably secured to the reflector 42a in any suitable manner, such as by spot welding.

FIGURE 14 shows a prior art construction wherein an object O to be heated is disposed in position for receiving heat from a bank of infrared heaters 150. Usually, the heaters are provided with symmetrical reflectors, such as previously described, so that the heat rays are directed generally at right angles from the heater, as shown by the arrows 151. If the end Oe of the object were to be heated, it was necessary for an end heater 15012 to be inclined inwardly, as shown in FIG. 14, in order to properly direct its heat rays 151e to the object end 02. This either decreases the width capacity of the heating oven or required the oven to be made considerably wider, in which case unnecessary expense was involved and efficiency of heaters was sometimes impaired.

This invention contemplates the use of a plurality of heaters 155 and an end heater 155e, all arranged in a straight line as shown in FIG. 15, to overcome the disadvantages of the construction shown in FIG. 14. The heaters 155 may be similar to the heaters referred to in FIG. 14 in that their reflectors are symmetrical. However, the end heater 155e is formed with an asymmetrical reflector 156, as shown in section in FIGURE 16, so that it combines with the heating element 157 to direct heat rays 158a at an angle other than ninety degrees such as the thirty-five degrees noted in FIGURE 16.

In view of the foregoing it will be apparent to those skilled in the art that I have accomplished at least the principal object of my invention and it will also be apparent to those skilled in the art that the embodiments herein described may be variously changed and modified, without departing from the spirit of the invention, and that the invention is capable of uses and has advantages not herein specifically described; hence it will be appreciated that the herein disclosed embodiments are illustrative only, and that my invention is not limited thereto.

I claim:

1. Electric infrared heating apparatus comprising a plurality of elongated, generally rectangular in cross-section heating modules in vertically stacked relation forming an upright, rectilinear wall, a heat-generating element carried by each module and a reflector adjacent each element for directing the heat rays emanating therefrom, the heat-generating element from the uppermost module extending longitudinally of and being adjacent an upper corner of said uppermost module and the reflector of said uppermost module having a relatively sharply curved portion adjacent said module corner and having a relatively less sharply curved portion adjacent a lower corner of such module to direct element heat downwardly.

2. An infrared heating element assembly, comprising an elongated box like sheet metal housing having an open side, a pair of hair-pin type elements within said housing, the terminal portions of the legs of each element extending from and being supported at respective ends of said housing and said elements being a combined length whereby the bights thereof are in facing but spaced relation within an intermediate portion of said housing, a reflector within said housing and behind said elements for reflecting heat rays from said elements outwardly of the open side of said housing, and a support member secured to said reflector and extending between said element bight portions for supporting the same, said support member comprising a sheet metal leg extending longitudinally of said housing and having a slot for closely receiving respective element bight portions therein, an intermediate portion of said leg having an opening into said slot to provide for ready disposition of the element bight portions therein.

References Cited by the Examiner UNITED STATES PATENTS 1,517,759 12/24 Shoenberg. 2,351,942 6/44 Dyer et a1 317-119 2,504,516 4/50 Goodell 219-400 2,521,232 9/50 Lashells 219-347 2,538,912 1/51 Road et al 339-31 2,688,685 9/54 Goodell 219-349 X 2,756,319 7/56 Hatch 219-405 X 2,782,390 2/57 Vincent 339-198 2,805,403 9/57 Road 339-31 2,822,457 2/58 Hatch 219-347 X 2,917,616 12/59 Thomson 219-347 X 2,957,154 10/60 Strokes 219-553 X 2,988,634 6/61 Miskella 219-536 X FOREIGN PATENTS 523,374 6/40 Great Britain.

695,284 8/ 5 3 Great Britain. 1,186,600 2/59 France.

OTHER REFERENCES New Infrared Equipment for Linear Heat Sources; The Fostoria Corporation; Fostoria, Ohio; brochure 59- 240; published 1959. 8 pages.

RICHARD M. WOOD, Primary Examiner.

MAX L. LEVY, Examiner. 

2. AN INFRARED HEATING ELEMENT ASSEMBLY, COMPRISING AN ELONGATED BOX LIKE SHEET METAL HOUSING HAVING AN OPEN SIDE, A PAIR OF HAIR-PIN TYPE ELEMENTS WITHIN SAID HOUSING, THE TERMINAL PORTIONS OF THE LEGS OF EACH ELEMENT EXTENDING FROM AND BEING SUPPORTED AT RESPECTIVE ENDS OF SAID HOUSING AND SAID ELEMENTS BEING A COMBINED LENGTH WHEREBY THE BIGHTS THEREOF ARE IN FACING BUT SPACED RELATION WITHIN AN INTERMEDIATE PORTION OF SAID HOUSING, A REFLECTOR WITHIN SAID HOUSING AND BEHIND SAID ELEMENTS FOR REFLECTING HEAT RAYS FROM SAID ELEMENTS OUTWARDLY OF THE OPEN SIDE OF SAID HOUSING, AND A SUPPORT MEMBER SECURED TO SAID REFLECTOR AND EXTENDING BETWEEN SAID ELEMENT BIGHT PORTIONS FOR SUPPORTING THE SAME, SAID SUPPORT MEMBER COMPRISING A SHEET METAL LEG EXTENDING LONGITUDINALLY OF SAID HOUSING AND HAVING A SLOT FOR CLOSELY RECEIVING RESPECTIVE ELEMENT BIGHT PORTIONS THEREIN, AN INTERMEDIATE PORTION OF SAID LEG HAVING AN OPENING INTO SAID SLOT TO PROVIDE FOR READY DISPOSITION OF THE ELEMENT BIGHT PORTIONS THEREIN. 